Lecture 5 - DA Flashcards
(49 cards)
Name 6 advantages of pesticides.
Name 4 disadvantages.
Advantages -Effective -Fast -Easy to use -Cheap -Broad spectrum -Increases productivity Disadvantages -Toxic to humans -Toxic to non target organisms -Persistent in the environment -Pests develop resistance
Name the 5 groups of pesticides.
Organochlorines Organophosphates Carbamates Botanicals Biologicals
What is the solubility (in water and lipids) of organochlorines like? What about its toxicity? Is it likely to persist in the environment?
Low solubility in water, high in lipids.
Toxicity is low-moderate.
Will bioaccumulate due to lipid solubility.
Which is more toxic, organochlorines, or organophosphates?
Which is more persistent?
Which degrades easier (and how)?
Organophosphates are more toxic.
However, they do degrade easier.
Organochlorines persist more.
Which is more water soluble, organochlorines or organophosphates?
Organophosphates.
Are carbamates more toxic than organochlorines/phosphates?
No, less toxic.
Do carbamates take long to degrade? What does this suggest about its persistence?
No, they degrade rapidly. Therefore, there are no problems with persistence.
What is the solubility of carbamates like?
Is variable.
Where are botanicals derived from?
Are pesticides derived from plants.
Are botanicals moderately toxic, or highly toxic?
Highly toxic.
Name 3 examples of botanicals.
Nicotine, pyrethrum, and pyrethroid.
What are 2 forms of pyrethrin?
Pyrethrum - natural form
Pyrethroid - synthetic form
What is one way pesticides can be classified?
By their mode of action.
How can analogues of juvenile growth hormones be used as pesticides?
Prevents the completion of the life cycle - perpetually in juvenile form.
What are 3 advantages of using juvenile growth hormones as pesticides? Name a disadvantage.
Is highly selective
Rapid degradation
Essentially non-toxic to other organisms
However, it will still affect bees.
What do antimetabolite pesticides prevent? What is a consequence of this? Are they highly specific or is there non-target toxicity?
Chitin synthesis. Failure to survive moulting.
There is some non-target toxicity.
Name 3 examples of biological pesticides (ie parasites, bacteria etc).
Fungi
Nematodes
Bacillus
What are some disadvantages of using biological pesticides?
Toxicity of ecotoxins, and affecting non-target insects like bees.
May also affect genetic stability.
Name 3 kinds of herbicides.
Triazine herbicides
Urea herbicidea
Phenoxy herbicides
What kind (in terms of persistence and selectivity) and dose of herbicide is needed for permanent removal of all vegetation?
High dose of a non-selective persistent herbicide.
What kind (in terms of persistence and selectivity) and dose of herbicide is needed for temporary removal of all vegetation?
Moderate dose of a non-selective non-persistent herbicide.
What kind (in terms of persistence and selectivity) and dose of herbicide is needed for selective removal of some plants, while leaving others?
Low-moderate dose of a selective herbicide.
How are herbicides taken in by plants? What characteristics are needed by the herbicide to be effectively taken up, and why?
Taken in via the leaves and stems above ground, and roots below ground.
Plant is covered by a lipid based cuticle, so the herbicide must be somewhat lipophilic.
Must also be slightly water soluble to be transported once through the cuticle.
What are the 3 selectivities of herbicides?
Differential uptake
Differential detoxification
Differential root growth habit.
